Fixed condenser and method of making the same



. O. BLAKE ET AL FIXED CONDENSER AND METHOD OF MAKING THE SAME March 7, 1933.

Filed Dec. 30, 1930 INVENTOR 0 b 1.. In [w \L In 9N L 8.", 8 WM a L 7 I||ril|||||1| (I fjave Blake a BJ arm 1% 11% -lJ- A RNEYS.

Patented 7, 1933 "UNITED STATES.

PATENT orr cs (IOTA-VB BLAIR AID 01 m Y. 816F038 TO am m0 murac'mnme 00., 180., O! MIG mm CITY, m YORK, L 003- POBA'I'IOI QI' NEW YORK m mono: sums m am A lication am mmao, mo. Iarlall'o. season.

This invention relates in fixed condensers of the woun necessarily limited thereto.

One of the objects of this invention is the provision of a novel form of fixed non-inductively wound condenser and the method of makmg the same. v V 1 Another object of this invention is to rovide a construction and method of ma d fixed condensers which are adapted to rapi and cheap manufacture because of simplicity of construction.

Another object of this invention involves a wax coated condenser with soft wire supporting leads which are partially enclosed in the wax coating which acts to make a strong and more rugged condenser. An important object of this invention is the provision of fixed condensers of a-type "as having permanent leads which are constructed so as to provide mounting supports for the neral to small d type but is not condensers.

Another object of this invention is the provision in a se f-supporting condenser of this typeof a rigid center core for supporting both the electrodes of the condenser and the supporting leadsin a manner to prevent strains on the electrodes of the condenser when the leads are deformed. A further object of this invention is the provision .of a wound fixed condenser employing a plurality of longitudinally over-lying strips of metal and nsulating material metal strips project laterally beyond the edges of the insulating strips. 4

.Another object of this invention is to em- Eloy overlying strips of this nature which ave diverging edges near the end so that the first few turns of the metal stri 5 project be yond the main body of the condenser to permit of connection thereto. 7

Astill further object of this invention is the provision of lead supporting ca s which fit over the projecting edges of t e metal strips and the central mandrel or core andsecured to the core'by metal tabs on the caps struck into the core through the metal strips.

Another object of this invention is the'pro- '50 vision of a paper dielectric condenser with tive location of shifted transversely in a manner so that the leads which provide the sole support for I Q These and other objects as will ap I from the following disclosure aresec by means of this invention.

This invention resides substantially in the go combination, construction, arrangement, relaarts, steps and series of steps, all as will he described in greater detail below. i

Referring to the drawing, as Figure 1 is a view of the mandrel and the alternate strips of insulating material and metal at the start of the winding operation Fig. 2 is a plan view of a condenser woun with the end caps in place;

' Fig. 3 is an end elevational view' of a wound condenser with the caps in place showing how the turns of one strip of metal are electrically in contact to make a non-inductive condenser; l

Fig. 4 is a plan'view of the condenser with the end caps a plied; Fig. 5 is a p anzview of a finished impreg nated condenser; a so" Fig. 6 is a plan view of a modified form of condenser not employing end caps;

Fig. 7 is another modified form employing metal clips in plaee'of the end caps; 1

Fig. 8 is a cross sectional view taken on the line 8-8 of Fig. 7. v It is broadly old to make fixed condensers by winding upon a mandrel strips of metal separated by layers of, insulating material which are super-imposed longitudinally and transversely in alignment. Condensers of this type are usually provided with leads which are connected to the metal strips without the I provision of means for su porting the leads so that, as they are bent, t ere is a tendency for the leads to tear the metal strips mining the condenser. 4 j

The condenser of this-invention oyercomesthis majordifiiculty. andglin'additiomg has no a position to be fixed in 10* many other features of advantages over prior center hole in the caps and are soldered on known constructions.

Referring to the drawing there is shown in Figurev 1, a core of mandrel made of suitable insulating material such as fiber, bakelite,'impregnate'd wood and thelike. This core, as shown in the form of a round rod, scored at separa'tedpoints, as indicated at 2, to provide a number of-cores 1 of the desired size. The core is mounted in a suitable winding machine so that the first section 1 is exposed for winding. The'metal strips 3 and 5 are constructed of any suitable, thin metal, such as tin-foil. A strip of thin, insulating material, such as wax paper, is shown at 4 lying between the metal strips 3 and 5. Under-lying the metal strip 5 is a similar strip of insulating paper 6. In accordance with this invention, the aper strips are in alignment. both longitudinally and: transversely. The metal strip 3 is shifted transversely with res ect to the-paper strips so as to extend a s ort distance there beyond as shown. and, in a similar manner, the other -metal strip 5 is shifted transversely in the opposite direction so as to extend a short distance beyond the paper strips. For a suitable distance from the end of these strips where the winding begins, the. strips are wider. As shown in this figure,

these strips gradually diverge from the point 7 to the end. while the remainder of the strips is of uniform width. It is of course apparent, that the wider end from the point 7 could be of uniform width and joined to thenarrower portion of the strips by a shoulder. It is immaterialhow the above result is secured just so long as the first few turns of the metal strips extend farther beyond the main body of the winding than the re-v maining turns. In other words, although all of the turns of the metal strips project beyond the insulating strips, the first few turns extend a greater distance than the remaining turns.

The mandrel or core is rotated causing the Y superimposed layers to wind up thereon un til the desired amount of material hasbeelifirst section 1 of the core is broken of at the wound to provide a condenser of a desired capacity. The strips, are then cut OR and the scoring 2. The core may then be advanced to expose the next sectionl for. winding. The condenser is in the state indicated in Fig. 2 when the winding is completed. the layer of paper 6 forming thelast turn to insulate the strip 5. from exterior contact. At the left, the first few turns of the metal strip 3 project as shownat 5 and, at the right, the first few turns of the metal strip 3 project as shown at 8. The caps 8 are of metal and are provided withsoftdrawn, copper wire leads 9 which are soldered thereto. In the form disclosed for illustration, the leads extend through a the interior wall thereof.

As shown in Fig. 4 the ca s are slipped over the ends of the core 1 an over the amjecting turns of the metal strips 5 an 3. Four diametrically opposed square punch holes are then made in the cap striking up.

by solderin or indeed by any present known method. n addition, the relatively stiff leads quickly tear the thin metal strips ruining the condenser. A very important feature of this invention is now apparent... Soft placing anystrain on the plates of the condenser since the core directly takes these strains. For this reason,.the leads 9 may be employed as the sole support for the condenser. Another feature of thisinvention is apparent from Fig. 3. As the condenser builds up during the winding operation, the projecting edges or the metal strips form into substantially, concentric cylinders.

When the winding of the condenser is fin-- ished, these projecting edg'es may be bent downwardly sothat all th layers of each drawn copper leads 9 soldered to the caps, I may be bent to any suitable shape without strip are forced into electr cal contact; the innermost turns contacting with the project-' ing edges 3 and 5. The result is, that all the turns of each plate of the condenser are in electrical contact producing a non-inductive fixed condenser. In the case of the small condensers, allthe plate turns are included under the end caps to insure interconnection between the plates. In the case of the larger condensers only a few of the turns of each plate are included under the caps, and the remaining turns are folded down over each other in succession as indicated in Fig. 3. The unit'of Fig. 5 is then immersed in asuitable, insulatin compound so that it is completely encase thereby, as indicated at;--

resistance and change its capacity.

In the modified arrangement shown in Fi 6, the condenser is wound to the point ind1- cated in Fig. 2 in the same manner as already a 100 in Fig. 5. As a result moisture cannot get into the condenser to reduce its dielectric described. In .this form metal caps. are not em loyed. The ends of the core 1- are provid ed with holes, 11 through which the ends of the leads 12 and 13 extend. The inner ends of these leads are wound around the projecting edges 3 and 5 of the metal strips to form the turns 13. This provides a contact between the leads 12 and 13 and" the metal plates. The entire condenser is coated with an insulating compound as described before. The insulating coating which may be of wax thoroughly protects the condenser and also acts to strengthen the wire leads. It will be noted that, as in the case of the first form described, the core 1 takes all the strains when leads 12 and 13 are bent. The moditied arrangement in Figs. 7 and 8, likewise comprise the wound member as shown in Fig. 2. In this case, instead of employing caps, U-sha ed clips 14 are provided which support t e leads 15. These caps slip over t e end of the core 11 which, in this case, is rectangular in form and are secured thereto by punched out tabs as indicated at 16. These tabs ext-end as before through the projecting edges of the metal strips 3 and 5 into the core 11. Here, likewise, the strains are taken b the core. This condenser is also coated wit a suitable impregnating compound.-

It is pointed out that although the invention is not limited thereto, the punch holes 10 and 16 are square so as to provide four tabs lying on the sides of a square which insure that the caps and clips are securely fastened to the core. The arrangement permits the core to take strains in all directions without loosening the caps or clips.

It is apparent from the foregoing description that we have provided a fixed non-inductive condenser which is relatively simple to manufacture and adapted to rapid and cheap production Without, in any way, sacrificing the quality thereof. Indeed by this construction, a very desirable and strong condenser results. The leads from the condenser are secured thereto to provide a support for the condenser and may be deformed without exerting any strains on the thin metal strips which comprise the condenser. The

member which is shown as a core need not necessa-nly be a central core since the advantages of this construction can be secured without havingthe member 1 at the center of the condenser.

Since then this invention resides in certain principles of construction and methods of procedure, it is not desired to be limited to the disclosure as given for purposes of illustration but rather to the scope of the invention as it is defined in the appended claims.

What we seek to secure by United States Letters Patent is:

1. A fixed condenser of the type described comprising a core, two metal strips mounted on said core and insulated from each other, i

the edge of one strip being exposed at one end of the core and the edge of the other strip being exposed at the other end of the core, said core having a transverse hole near each end and leads extending through said holes and in contact with the exposed edge of each trip respectively.

coiled at the ends, the coils being conductive ly connected to the foils, and means for securing the leads to said supporting member. In testimony whereof we have hereunto set our hands on this 13th da of Dec. A. D., 1930.

O TAVE BLAKE. HAIM BEYER. 

